BOSTON — It seems as though Boston Bruins general manager Peter Chiarelli lives by the philosophy of “offense wins games, but defense wins championships.”

The first-year GM traded forward Brad Boyes and defenseman Paul Mara in separate deals for defensemen Aaron Ward and Dennis Wideman before the 3 p.m. trade deadline yesterday. Wideman, 23, was acquired from St. Louis for Boyes. Ward, 34, was obtained from the New York Rangers in exchange for Mara.

Ward is a three-time Stanley Cup champion — two in Detroit and one in Carolina — and for all his on-ice attributes, it will be his vocal leadership off the ice that the Bruins need at this point. Chiarelli said Wideman will bring energy and youth to the back side.

“Both of these moves were made to shore up our defense,” said Chiarelli. “We’ve given up a lot of goals and we felt these moves were in the right direction to shore up our defense. … If you lump these two transactions together with our other trade (acquiring defenseman Andrew Ference and forward Chuck Kobasew on Feb. 10 for defenseman Brad Stuart and forward Wayne Primeau), we believe we’ve really improved our defense. That was a big objective.”

With the Bruins dealing Boyes, it’s the second time this season the organization has given up on youth. On Feb. 1, Chiarelli dealt 23-year-old blue-liner Milan Jurcina to Washington for a fourth-round pick (2008).

Boyes has an incredible work ethic and is well liked by his peers. After a tremendous rookie season last year (26 goals, 43 assists for 69 points in 82 games), his game struggled this season. With his role a bit different this year under new head coach Dave Lewis, Boyes finally started to come around of late, proving he is a talented young forward.

“To get something you have to give up something,” said Chiarelli. “Brad is a good player, don’t get me wrong. He’s a good player and he had a very good year last year, I understand that.”

Lewis said Boyes’ play was inconsistent and had confidence problems at times this season.

“This year is definitely different than last year,” said Boyes. “Different management and a different coach and I tried to make the best of my opportunities. There are guys here I’m going to miss. I’m going to miss playing with Bergy [Patrice Bergeron] and a couple of the other guys. Now, I have a new opportunity.”

“He is one of my best friends on the team,” said Bergeron. “It’s tough to see him go. Obviously I wish him all the best and I hope it’s a good thing for him, and for us, too. I really wish him all the best.”

Boyes, a former first-round pick (24th overall) by Toronto in the 2000 NHL Entry Draft, has been traded before — first to San Jose, then to Boston and now to St. Louis.

Over the last few days leading to the trade deadline, his name was part of the rumor mill and he admitted it was weighing on his mind. After 3 p.m. came and went, Boyes thought he was in the clear and would remain a Bruin. Shortly before 4 p.m., he learned of the deal.

“I thought, ‘Well, I guess I’m staying.’ When I heard it after, I was surprised a little bit,” he said. “At the same time I’m excited to go to St. Louis. The Blues have made a lot of moves lately, especially the last couple of days. I’m looking forward to going there and getting another opportunity again.”

Mara was acquired by Boston last summer from Phoenix in exchange for Nick Boynton. Mara was coming off a career year for the Coyotes, but couldn’t continue that success here this season.

“I really like Paul as a person,” said Chiarelli of the Belmont, Mass., native. “I think he had some pressure playing here in his hometown.”

When Lewis was an assistant in Detroit, he said he spent a considerable amount of time with Ward during his “developmental” years and is looking forward to working with him again. When Chiarelli was a players’ agent, he represented Ward.

“Anytime you can get a player who has won a Stanley Cup, it is a real plus,” said Lewis. “He contributes and can play 20 minutes. I don’t think you can ever have enough of those guys who have been around winners. He’s experienced it in a couple of different cities, which is unusual. He’s excited about getting here and I’m looking forward to meeting with him.”

As the Bruins attempt to sneak into the playoffs, most of the players in the locker room lead by example. Ward is the kind of guy who isn’t afraid to speak his mind and that could be an ingredient Boston desperately needs.

jmcdonal@projo.com